We have performed the electronic band structure calculations for type II InAs/InxGa1-xSb strained layer SLs by using three different techniques (a) a modified tight-binding, (b) an eight-band k.p method, and (c) an effective orbital model, and discussed their relative strengths and weaknesses.
An important boundary condition that has been considered in all three methods for the band structure calculations is the band line-up at the interface, as the calculated results are very sensitive to the band alignment. Before strain, it is assumed that the two-fold degenerate valence band edge in the InxGa1-xSb layer is 0.51 eV above the two-fold degenerate valence band edge in the InAs layer, regardless of x. The uniaxial component of the strain then splits the two-fold degeneracy in each layer as the light-hole band edge moves above the heavy-hole band edge in InAs layer and below the heavy-hole band edge in the InxGa1-xSb layer.